[patch] Fix for BZ 22207 -- intermittent failure to create threads on 32-bit machines

[Paul Pluzhnikov]

Greetings,

In stdlib/test-{atexit,at_quick_exit,cxa_atexit,on_exit} tests, I am
creating 1024 new threads.

With default 8MiB Linux thread stack size, if all threads are alive at
the same time, this would require 8GiB of VM, which is a bit of a
problem on 32-bit machines.

Attached patch reduces total VM space required for all threads to 128MiB.

Proposed commit message:

---
Reduce total memory required to create all threads to 128MiB.

This fixes intermittent failure in
stdlib/test-{atexit,at_quick_exit,cxa_atexit,on_exit} tests (Bug
22207).
---

Thanks,
-- 
Paul Pluzhnikov
-------------- next part --------------
2017-09-25  Paul Pluzhnikov  <ppluzhnikov@google.com>

	[BZ #22207]
	* stdlib/test-atexit-race-common.c (do_test): Minimize required
	VM size.

diff --git a/stdlib/test-atexit-race-common.c b/stdlib/test-atexit-race-common.c
index b3792837c7..3a03e06cb9 100644
--- a/stdlib/test-atexit-race-common.c
+++ b/stdlib/test-atexit-race-common.c
@@ -57,6 +57,11 @@ do_test (void)
   xpthread_attr_init (&attr);
   xpthread_attr_setdetachstate (&attr, 1);
 
+  /* With default 8MiB Linux stack size, creating 1024 threads can cause
+     VM exhausiton on 32-bit machines.  Reduce stack size of each thread to
+     128KiB for a maximum required VM size of 128MiB.  */
+  xpthread_attr_setstacksize (&attr, 128 * 1024);
+
   for (i = 0; i < kNumThreads; ++i) {
     xpthread_create (&attr, threadfunc, NULL);
   }